Shutter-operating mechanism for photographic cameras.



R. HEIDEGKE.

SHUTTER OPERATING MECHANISM FOR PHOTOGRAPHIG CAMERAS. 121 1110111101;FILED DBO. a1, 1912.

' 1,075,101. Patented 0013.7,1913.

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ammonia nmnncnn; or BRUNSWICK, GER=MANY;7ASS-IG1\TOR TO VOIGTLAENDER &

sonn,nxrrnncnsnmscnerr, BRUNSWICK, GERI/IANY, or BRUNSWICK, GER- MANY; ACORPORATION QFGERMANYJ SHUTTER-OPERATING MECHANISM son rnorcs'n'nrn'rcCAMERAS.

Specification of Letters Patnt.

Patented Oct. 7, 1913.

Application filed December 31,1912? Serial No. 739,507.

Toallwhom it may concern-1 Be it known that I, REINHOLDHEIDECKE,workmaster, citizen of the Duchy of Bruns- WlOl, Empire of Germany,residing .at Brunswick, Germany, have invented certain new and usefulImprovementsin- Shutter- Operating Mechanisms for Photographic 7Cameras, of which the following is a specification.

My invention relates to improvements-in shutter" operating mechanismsfor photographic cameras, and more particularly in operating mechanismsof that'class in which the shutter is opened and closed again by meansof a spring actuated member which is normally locked in inoperativeposition and begins itsmovementfor operatingthe shutter afterit has beenreleased. After the 1 said member has opened the shutter it meets aretarding-device which is connected with braking means adapted toprevent: rapid movement, so that the retarding device can but slowlyrec'ede from the opening memher. After the retardingndevice has beenpushed backward to a certain point, the shutter is closed? In apparatusnow'in use the bra-king means are provided by toothed gearings the 2resistance of which produces the braking action. In some cases thisbraking action 'is I increased" by means of a wind wheel connect- 3 edwith the gearing: The braking action and thereby the time during whichthe shut- I ter keeps the camera open-"is varied by vary ing themomenbat which'the retardingde vice gets into 'the path of the closingmemher. If 'with'apparatus of this construction a very short exposure isrequired, and'therefore the retarding device exerts'its braking actionon theshutter operating member dur ing a very short part of the strokeofthe latter and on a small part of its path comparatively much time isrequired before the retarding devicegets out'iof the way'of-theoperating member, because by reason of'the inertia ittakes-comparatively mu'ch time to set the gear wheels into motion.If'onthe other hand the masses of the said gear wheels-are reduced, itis not possible-*to open the shutteras long as is required for longerexposures-because the r-esistance of the/parts is rapidly reduced afterthe masses have once acquired a substantially constant speed, becausethenonly the resistance caused by friction must be overcome.

' The object of the improvementsis to provide a mechanism in which theseobjections are avoided.

With this object in view my invention consistsin constructing themechanism in such a way, that its resistance is gradually increasedwhile it is in operation. For this purpose between the retarding deviceand the mechanism'which provides the braking means and which is inoperative connection withthe retarding device and'controls the speedwith which it recedes, a transmission gearing is interposed which has avarying ratio of transmission. Gearings of this kind are for exampleelliptical gear'wheels, antiparallel cranks, rotating cam slots, etc.The mechanism is so disposed, that at the beginning-the velocity of themovement transmitted from the retarding device to the braking meansisreduced andthat the transmission is gradually changed, so that finallythe velocity is increased by'the transmission gearing, and the ratioofthe numbers of 'rev'olution of'the-parts is'reduced the longer-themovementlasts. I Therefore, at the beginningpf the movement the retarding'device is shifted at a greater speed as-com'pared tothenumber'of revolutions-of the mechanism, and its: comparative speed isgradually reduced: I

In order that my invention bemore-clearly understood anexanrpleembodying the same hasbeen shown-in the accompanying drawing', :inwhichthe same letters of reference have been used in all the views toindicate corresponding parts.

. In said drawingFigure '1, is a diagrammaticalside' 'view' of themechanism, Fig. 2, is a similar side view of the left hand part of themechanism" showing the' connection betweenfthe" retarding device, itssetting member andthe slide bar of the braking means, and Fig. 3, is asimilar side view showing :the mechanism for returning the slide barinto ini-tistl-position;

. To a rotary disk a which is acted upon by a springtnotshowHMa pin a issecured which has the function to operate the shutter mechanism. Thisshutter mechanism is known in the art and needs no detailed description.Normally the disk 0 is locked by means of a locking member Z; which isadapted to be thrown into non-locking position by means of a rockinglever d carrying a key d. Then the disk 0 is thus released, it isrotated by its spring so as to operate the shutter mechanism. In case ofvery short snap shots the disk 0 rotates without any interruption, untilit has completed its movement, that is, until a shoulder 0 formed on thedisk strikes against a relatively fixed stop f. When the disk 0 is thusrotated, the pin a opens and closes the shutter.

If a short time exposure is desired, a movable retarding device 9 isbrought into the path of the shoulder 6, before the latter reaches thestop f by which the end position of the disk 0 is determined. Theretarding device 9 has the function to delay the movement of the disk 0.It is so constructed, that it gradually recedes under the pressureexerted thereon by the shoulder e. For this purpose it is constructed inthe form of a lever which has a rocking support on a pivot it, and it isconnected by means of a link i with a slide rod 70 formed with rackteeth is. The rack is in engagement with gear wheels Z the object ofwhich is to provide a brake for retarding the movement of the slide bar70 and the disk 0. These parts are known in the art. They will thereforebe fully understood from my brief description thereof.

Referring now to those parts to which my invention more particularlyrelates, the transmission of the movement of the rack 70 to the gearwheels Z is effected in the example shown in the drawing by ellipticalgear wheels m, m which are so disposed, that at the beginning of thereceding movement of the retarding lever g and at the beginning of themovement of the slide is in the direction of the arrow shown in Fig. 1the velocity is reduced by the elliptical gear wheels, and that theratio of transmission is gradually changed, so that the velocity isfinally increased by the gear wheels. Therefore at he beginning of themovement the starting of the gear wheels Z and m requires less powerthan near the end of the movement.

The initial position of the slide bar is must be the same for all thedifferent xposures. Therefore in my improved mechanism means areprovided whereby the slide 70 is prevented from takin part in thesetting operation of the arresting member. As will be understood, thisoperation determines the time of the exposure which depends on theposition of the retarding lever relatively to the shoulder 6. Thereforein case of a shorter or longer exposure the resistance of the retardinglever g has always at the beginning of its movement the smallest value,whereupon it is gradually increased. In case of a very short exposurethe said resistance is but slightly increased as compared to itssmallest value.

In the example shown in the drawing Fig. 2. the slide bar In is madeindependent of the retarding lever g by connecting the retarding lever gand the slide bar 70 by means of a toggle joint, which consists of alink n jointed with its end 9 to the slide bar 70, and a link p thepivot 0 of which can be set by any known or preferred means, as has beenindicated in Fig. 2 by the arrows pointing in opposite directions fromthe pivot 0. The rocking lever g engages in a longitudinal slot made inthe link 39. In Fig. 1 this toggle joint has been omitted, in order thatthe figure be as simple as possible. The retarding lever g is set byshifting the pivot 0 in the direction of the arrows shown in Fig. 2, andif this is done, the link a rocks about its pivot 9, While the slide bar70 remains at rest. If however the pivot 0 is held in fixed position,and the arresting member 9 is operated by the shoulder e, the slide baris is shifted.

It may be added, that the slide bar 70 which during the exposure isshifted to the left must be returned into initial position, before theshutter is again opened. To show what may be done, a bell crank lever ris provided which with one end is in position for shifting the slide bar76 to the right and into initial position and with its other arm in thepath of the pin a. When the disk 0 is turned in the direction of thearrow shown in Fig. 3 and its spring is put under tension, the bellcrank lever 1- is rocked so as to shift the slide bar 70 into initialposition. By the same operation the rocking lever g is shifted into itsposition in which it is ready to retard the disk 0.

I claim herein as my invention:

1. In a shutter mechanism for photographic cameras, the combination witha device taking part in the opening and closing movements of theshutter, of a member adapted to be thrown into cooperation with saiddevice, rotary braking means, and transmission gearing intermediate andoperatively connecting said member and braking means, said transmissiongearing having an increasing ratio of transmission.

2. In a shutter mechanism for photographic cameras, the combination witha device taking part in the opening and closing movements of theshutter, of a member adapted to be thrown into cooperation with saiddevice, rotary braking means, and elliptical transmission gearingintermediate and operatively connecting said member and braking means,said transmission gearing saving an increasing ratio of transmission.

In testimony whereof I have hereunto set 3. In shutter mechanism forphotographic my hand in presence of tWo subscribing Witcameras, thecombination with a member operable during the closing movement of thenesses. shutter, of retarding mechanism comprising REINHOLD HEIDECKE. abrake, and means for transmitting move- Witnesses:

WILHELM LEHRKE, KARL MUNDT.

ment from said member to said brake at an mcreasmg ratio oftransmlssion.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. 0,

